lOO 
EXTINCT MONSTERS. 
two distinct species. The larger one, Iguanodon Bernissartensis, 
cannot be less than fifteen feet high, and, measured from the tip 
of the snout to the end of the tail, is rather over thirty feet long, 
covering nearly twenty-four feet of ground in its erect position 
(see Fig. 21). Iguanodon Mantelli is smaller and more slender 
looking, with a height of over ten feet, and a length of about 
twenty feet. (See Fig. 22.) 
The huge three-toed impressions found in Sussex prove that 
the monster, although owning a body as large as that of an 
elephant, habitually walked on its hind legs ! Some of the thigh- 
bones found by Dr. Mantell measured between four and five feet 
in length. It will be seen that the fore limbs are small in com- 
parison to the hind limbs. A remarkable feature of the hand is 
the large pointed bone at the end of the thumb, forming a kind of 
spur. The conical shape of this bone found by Dr. Mantell, who 
